Mesonephric-like Adenocarcinoma of the Uterine Corpus: Genomic and Immunohistochemical Profiling with Comprehensive Clinicopathological Analysis of 17 Consecutive Cases from a Single Institution

Clinicopathological Significance of Claudin-6 Immunoreactivity in Low-grade, Early-stage Endometrioid Endometrial Carcinoma

BACKGROUND/AIM

Dysregulation of claudin 6 (CLDN6) expression has been widely documented in various malignancies. CLDN6 is aberrantly expressed in many types of human carcinomas; however, its clinical significance in endometrial carcinoma has seldom been investigated. This study aimed to examine the immunohistochemical expression status of CLDN6 in low-grade, early-stage endometrioid endometrial carcinoma (LGES-EEC) and to assess its clinicopathological significance.

MATERIALS AND METHODS

We performed immunostaining for CLDN6 in 118 tissue samples from LGES-EECs. Protein expression levels were interpreted using a semi-quantitative histoscore method. All statistical analyses were performed.

RESULTS

CLDN6 was primarily localized along the membranes of the tumor cells. We considered histoscore ≥10 (the staining proportion ≥5% and intensity ≥2) as positive immunoreactivity for CLDN6. Twenty-six of the 118 patients (22.0%) showed CLDN6 positivity. Positive CLDN6 expression was significantly associated with deeper myometrial invasion (p=0.001), higher initial stage (p=0.015), and substantial lymphovascular space invasion (p=0.018).

CONCLUSION

Aberrant CLDN6 expression is involved in tumor progression in LGES-EECs. In addition, targeting CLDN6 may offer clinical utility in patients with endometrial carcinoma.

Lymphangioleiomyomatosis of the Pelvic Lymph Nodes Detected Incidentally During Surgical Staging of Gynecological Malignancies: Comprehensive Clinicopathological Analysis of 17 Consecutive Cases from a Single Institution

BACKGROUND/AIM

Lymphangioleiomyomatosis (LAM) belongs to the perivascular epithelioid cell tumor (PEComa) family. The relationship between LAM and tuberous sclerosis complex (TSC) is of particular concern in a subset of women with clinically occult LAM involving the pelvic lymph nodes. This study aimed to investigate the clinicopathological features of incidental nodal LAM detected during the surgical staging of gynecological tumors.

PATIENTS AND METHODS

During the study period of 10 years, we identified 17 patients with pelvic nodal LAM that was incidentally detected during surgery for gynecological neoplastic lesions. We conducted immunostaining to assess the diagnostic utility of a panel of PEComa markers.

RESULTS

Two of the 17 patients (11.8%) were diagnosed with TSC before surgery without any pulmonary symptoms. During the follow-up, both patients developed pulmonary and extrapulmonary LAMs. All affected nodes were multiple and unilateral in the pelvic region. The mean nodal size was 5.4 mm, and the mean proportion of the area involved in the LAM was 34.1%. In two patients with TSC, the largest affected node measured 19.3 mm and 7.6 mm, respectively, and the proportion of the area replaced by LAM was 99% and 90%, respectively. The most frequently expressed markers were human melanoma black 45 and cathepsin K, which showed 100% positivity in all the examined cases.

CONCLUSION

While most small nodal LAMs incidentally discovered during surgery have insignificant prognostic value, larger nodal LAMs occupying most of the nodal parenchyma at reproductive age should raise awareness of pulmonary and extrapulmonary LAMs as well as TSC.

Ovarian Metastasis from Human Papillomavirus-associated Usual-type Endocervical Adenocarcinoma: Clinicopathological Characteristics for Distinguishing from Primary Ovarian Mucinous or Endometrioid Tumor

BACKGROUND/AIM

Distinguishing ovarian metastasis of usual-type endocervical adenocarcinoma (UEA) from primary ovarian tumors is often challenging because of several overlapping features. This study aimed to investigate the clinicopathological characteristics and outcomes of patients with metastatic ovarian UEA.

PATIENTS AND METHODS

Clinicopathological information was collected from eight patients with metastatic ovarian UEA. Immunostaining was also performed.

RESULTS

Most patients presented with adnexal masses that were suspected to be primary ovarian tumors. All examined cases showed block p16 positivity in paired primary and metastatic tumors. Five patients who completed post-operative chemotherapy or concurrent chemoradiotherapy (CCRT) did not experience recurrence. In contrast, one patient who refused further treatment after the first CCRT cycle experienced ovarian and peritoneal metastases. One patient with isolated ovarian metastasis left untreated and developed peritoneal metastasis during follow-up.

CONCLUSION

Patients with UEA who received proper management for ovarian metastases showed favorable outcomes. Given that ovarian metastatic UEA can mimic primary ovarian borderline tumor or carcinoma of the mucinous or endometrioid type, pathologists should be aware of this unusual but distinctive morphology to avoid misdiagnosis and inappropriate treatment.

Dedifferentiated Leiomyosarcoma of the Uterine Corpus with Heterologous Component: Clinicopathological Analysis of Five Consecutive Cases from a Single Institution and Comprehensive Literature Review

Dedifferentiation is a very rare phenomenon in uterine leiomyosarcoma (LMS). The aim of this study was to comprehensively analyze the clinicopathological characteristics of uterine dedifferentiated LMS (DDLMS). We reviewed electronic medical records and pathology slides from five patients with uterine DDLMS and performed immunostaining. The mean age of the patients was 56 years. Two patients presented with abdominal discomfort, while in three cases the uterine tumors were detected on routine medical examination. The mean size of the tumors was 17.0 cm. Four patients underwent hysterectomy. The initial stages were distributed as IB (2/5), IIIC (2/5), and IVC (1/5). Post-operative concurrent chemoradiation therapy, radiation therapy, and chemotherapy were administered in one, one, and two patients, respectively. Despite post-operative treatment, three patients developed metastatic recurrences in the abdominal and pelvic organs. Recurrence-free survival time ranged between 4 and 30 months. Histologically, the differentiated areas demonstrated the classic morphology of malignant smooth muscle differentiation, whereas the dedifferentiated areas resembled undifferentiated pleomorphic sarcoma and were characterized by large pleomorphic tumor cells admixed with haphazardly arranged atypical cells with marked nuclear pleomorphism. All cases also exhibited heterologous components, including chondrosarcoma (CSA; 3/5) and rhabdomyosarcoma (2/5). In two cases, the heterologous components were initially detected in primary tumors. In three cases, the primary tumors did not exhibit any dedifferentiated or heterologous components. Instead, more than half of the recurrent tumors consisted of heterologous components. Three cases showed a sharp demarcation between the LMS and CSA components, while in two cases the dedifferentiated area imperceptibly merged with the differentiated component. Immunostaining revealed that the dedifferentiated components exhibited a lack of desmin immunoreactivity in three of the four examined cases. A subset of uterine LMS represents various amounts and types of dedifferentiation and heterologous components in both primary and recurrent tumors. Routine recognition of DDLMS and distinction from its mimickers are required for accurate diagnosis and further characterization of these rare tumors.

Endocervical Adenocarcinoma Showing Microcystic, Elongated, and Fragmented (MELF) Pattern of Stromal Invasion: A Single-Institutional Analysis of 10 Cases with Comprehensive Clinicopathological Analyses and Ki-67 Immunostaining

Microcystic, elongated, and fragmented (MELF) pattern of invasion has seldom been documented in endocervical adenocarcinoma (EAC). The aim of this study was to analyze the clinicopathological characteristics of EAC showing MELF pattern. We collected the clinicopathological information of 10 cases of EAC with the MELF pattern and conducted polymer-based immunostaining for Ki-67 (dilution 1:200, clone MIB-1) on these cases. Ki-67 expression was assessed using the average estimation within the hotspot method. All tumors were human papillomavirus-associated EAC with Silva pattern C. All except one tumor exceeded 3 cm in size. Five tumors involved the entire thickness of the cervical stroma, and four tumors extended into the parametrium. Lymphovascular space invasion was identified in six cases. Two patients developed metastatic recurrences in the para-aortic lymph nodes and lungs, respectively. The MELF area showed significantly lower Ki-67 labelling index than that of a conventional tumor area. We confirmed our previous observation that the MELF area displayed lower proliferative activity than the conventional tumor area of EAC. We also demonstrated that patients with EAC showing MELF pattern had several adverse clinicopathological characteristics reflecting aggressive behavior. On the other hand, since the frequencies of post-operative recurrence and disease-related mortality that occurred during the follow-up period were relatively low, further investigations are warranted to clarify the prognostic value of MELF pattern in EAC patients.